here is a photo of a First bus for comparison...
31 buses are in the process of being delivered ot ON garage for route 83 [but they appear on the 79 & 92], and another batch would go for the 476 and probably 259 [NP]- total of 76 - which was diverted from the national order [those 76 were meant for Manchester].
Quite possible... I do not really look at night buses- too late for me
but those VNs would be used on route 18 on the August bank holiday- the second day of the Notting Hill Carnival as extras between sudbury and the carnival area.